The present invention relates to high density storage systems of the type having a plurality of individual movable storage units. More particularly, the present invention relates to an improved design for the wheel and tracks for the high density storage system.
High density storage systems have typically consisted of rows of storage sections. Each row is supported upon a common base and is movable upon spaced parallel tracks through the provision of roller mechanisms or the like. The length of the parallel tracks are roughly equal to the total dimension of the various storage units when they are placed directly adjacent one another, plus the width of an access aisleway through which a person may have access to the individual shelf sections. These prior art high density storage systems thus enable access to various individual storage sections as desired while minimizing space requirements for the overall system.
The designs of certain of such prior high density systems have, however, certain disadvantages due to the designs of the wheels, the tracks and the interface between these two components. The wheels which ride along and mate with the track exhibit a tendency to derail from the track under various movements of the individual storage units. This tendency is more prevalent in both the heavy duty designs of storage systems as well as when the system requirements dictate a relatively thin or minimal depth storage unit.
Prior art designs of wheel and track members are shown in FIGS. 1 and 2. Both of these wheel and track systems are designed to utilize tracks which reduce the need to provide accurate leveling of the track so the system may be utilized on relatively irregular support surfaces. FIG. 1 shows a wheel 110 rotatably mounted to an axle 112 and positioned on the axle by a pair of bushings 114. The exterior surface 116 of the wheel 110 is adapted to mate with the track 118 as shown in FIG. 1. Track 118 consists of a generally triangular base 120 having a cylindrical running surface 122 disposed within the triangular base 120 as shown in FIG. 1. While this configuration is acceptable for certain applications, this design has a tendency to easily derail when any type of side load is generated between the wheel and the track. The presence of a side load easily ramps the wheel 110 up and over one of the angular surfaces of the triangular track 118.
FIG. 2 shows another type of prior art wheel and track design. In this design, a wheel 130 is rotatably mounted to an axle 132 and positioned on the axle by a pair of bushings 134. The exterior surface 136 of the wheel 130 is generally cylindrical. The track 138 consists of a generally triangular base 140 but instead of incorporating a cylindrical running surface similar to FIG. 1, base 140 has a longitudinally running generally V-shaped groove 142. The V-shaped groove has a pair of inserts 144 which run the entire length of the track 138. These inserts provide a pair of running surfaces for the wheel 130. The wheel 130 contacts the inserts 144 at points 146 and 148. This design of track, while improving on the problem of derailment, does not eliminate the derailment issue. Due to the relatively shallowness of the V-shaped groove, the wheel can still be relatively easily derailed from the track.
It is, therefore, desirable to provide a new and improved high density storage system which incorporates a wheel and track system which is less sensitive to the tendency of the storage unit to derail. It is further desirable to provide such a stable high density storage system which also reduces the need to provide accurate leveling of the associated tracks upon which the storage units are supported and guided for movement so that the system may be utilized on relatively irregular support surfaces.
The above and other features of the invention will become apparent to those skilled in the art from the subsequent detailed description, appended claims and drawings.